For track use, slotted is the best bet. Slotted will allow you to be able to run racing friction material if you wish.

This is also true of plain discs, but slotted provide the additional advantage of refreshing the pad surface. This promotes more higher and more consistent performance, and can actually extend disc life.

On a drilled or slotted disc, if you observe the outer edge of the disc where the slots or holes do not sweep the pad surface, you will generally find that this area of the disc wears faster than the main surface where the pad is swept by the holes or slots. (Of course, the extreme outer edge may be a ridge where the pad does not touch the disc at all, so I am not referring to this.)

 

Here is an update, my car should be back from the shop with a new guards LSD and custom transmission cooler installed. The entire project is pretty substantial because it’s on top of an engine removal for the water fitting issue. All new hoses, water pump, Crankshaft underdrive pulley, intake plenum, new exhaust, new water reservoir and a tranquilizer to be calm enough to write the check. Well one may ask, what does this have to do with a brake thread? Well…if you have read my of my earlier posts, my PSM has been really intrusive with my brakes on the track and the LSD is the best fix (short of getting a GT2 or GT3). I will report back once I have some track time on my car but it may be several months. There are only a few open track days left this year and the weather is ugly in Washington State this time of year.

 

Guys, so just to 100% confirm, 997t brake calipers (red) are a direct fit on to a 996t across all year ranges?

 

Yes, when used with 997TT 350x34mm front discs as well.

 

For those that are upgrading to 6 spots, what are you doing for a spare wheel? The standard collapsable spare is 16" but with the 6 spots you need a 17" wheel. Are you just sticking a can of spray goo in the boot or buying a 17"wheel?

 

Fronts are a direct fit but not the rears. The 997tt rears will bolt up but the caliper piston area is different that in the 996tt and will mess with your ABS/PSM due to nonstandard brake proportioning. You will have too much brake pressure going to the rear if you use 997tt calipers.......There is a guy (MSV) on this site that is a Brembo engineer and he went into a detailed explanation on this and cautioned that using 997tt rear calipers on a 996tt is quite unsafe....do a search on his posts and you should be able to find it...it may actually be somewhere earlier in this thread..

 

Glad to see you guys are keeping this thread and the technical aspects of it alive.

Well Done!
Mike

 

Hello.

If possible, I would like the author (or someone) to please comment on this:

Front Brake Issues
GT2/3 Calipers - Direct bolt on
GT2/3 Rotors - NOT a direct bolt on.

As I have understood, this means, that GT2/3 brake discs cannot be mounted on 996 Turbo w/o changing other parts of the suspension.

However, on our Russian forum a few people claim it is not true and also tell me they were able to install GT2 discs (steel) and calipers on a regular 996 Turbo and it ran fine.

Can you please explain in detail WHY GT2/3 discs are NOT a direct bolt on for a 996 Turbo? And exactly, how do brake discs relate to struts and other parts of the suspension?
I understand, they are just discs which are mounted on the hub, why does one need to replace struts and other stuff?

Thanks a lot!

 

The GT2/3 calipers are a direct bolt on I believe. The rotors off these cars will bolt on but you will find that the offset of the rotor is incorrect so the disk will not run in the centre of the gap where the pads sit.

 

Correct. There is a 2-3MM difference in the rotor "Bell" or "hat" offset. In order to use the GT2/3 rotor, you need to employ a spacer under the rotor to correct the distance.

Mike

 

Thanks a lot for the answer. I wonder why they made GT2/3 rotors different? Was it because they wanted them to clear OEM Turbo twist wheels?

 

You need to run a spacer on turbo rotors to have them fit a GT, but you'd need to machine the inside face of a GT rotor hat to get it to fit a turbo and this might compromise the strength of it.

 

NBTBRV8 is correct.

The offset (hub face to inside face of disc) on a GT2/GT3 disc is 61mm. On a Turbo it is 63mm.

 

Subscribed.

 

Sorry guys I may have missed the information but if you want to use the 996TT REAR caliper with the 997TT 350mm REAR rotor is a caliper spacer required? If so, which vendor do you guys recommend for that?